Drive for deep-well sucker-rod pumping unit

ABSTRACT

A sucker-rod pumping unit for fluid withdrawal is disclosed which relates to the oil producing industry and may be used in other industrial and agricultural sectors. The objective of the invention is to provide an improvement of kinematics to extend the range of use of a drive for the deep-well sucker-rod pumping unit. The drive comprises an electric motor coupled through a central gearbox to differentials comprising pinions and wheels, each differential having an output shaft and a housing fixedly coupled to a crownwheel. The housing of each differential, which is fixedly coupled to the crownwheel, is coupled through a crank to a pitman arm. In the meantime, the pitman arms coupled to the cranks fixedly coupled to the crownwheels are coupled through yokes to an equalizer on a walking beam, or the pinions of the differentials engage the output shaft of the central gearbox.

FIELD OF INVENTION

The invention relates to the oil producing industry and, in particular, to a sucker-rod pumping unit for fluid withdrawal, and may be used in other industrial and agricultural sectors.

BACKGROUND

RU 2278994 (25 Oct. 2004) discloses a drive for a deep-well sucker-rod pumping unit. The drive comprises a motor, a gearbox, an assembly consisting of two pitman arms, at least one pinion and two central wheels. The at least one pinion and one of the central wheels or the two central wheels are coupled to the pitman arms, and the pitman arms having other ends coupled through a walking beam to the deep-well sucker-rod pumping unit or directly to sucker-rods. This drive is insufficiently reliable and long-lived.

RU 2463479 (28 Dec. 2009) discloses a drive for a deep-well sucker-rod pumping unit. The drive comprises a motor coupled directly or through a gearbox to a differential comprising at least one pinion and two wheels. The drive comprises at least one further differential. Each differential has an output shaft and a housing fixedly coupled to a crownwheel. The output shaft and the housing of each differential are coupled to cranks and pitman arms. The main drawback of such a drive is its insufficient kinematics that restricts its use.

The present utility model is intended for solving the problem of how to modify the drive design such that it provides improved kinematics, thereby extending the range of use of the drive.

SUMMARY

The problem above is solved by a drive for a deep-well sucker-rod pumping unit, which comprises an electric motor coupled through an intermediate gearbox to differentials comprising pinions and wheels, each differential having an output shaft and a housing fixedly coupled to a crownwheel. The housing of each differential, which is fixedly coupled to the crownwheel, is coupled through a crank to a pitman arm. Furthermore, the pitman arms coupled to the cranks fixedly coupled to the crownwheels are coupled through yokes to an equalizer on a walking beam. The pinions of the differentials engage the output shaft of the central gearbox.

The technical result provided by the above-indicated set of features is an improvement of kinematics that allows extending the range of use of the drive due to the coupling of the housing of each differential, which is fixedly coupled to the crownwheel, through the crank to the pitman arm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a drive for a deep-well sucker-rod pumping unit, i.e. an external view of a pump jack (left-side view).

FIG. 2 schematically shows a cutaway view of a central gearbox assembled with differentials (cutaway view C in FIG. 4).

FIG. 3 schematically shows the drive for the deep-well sucker-rod pumping unit in stowed configuration.

FIG. 4 schematically shows the drive for the deep-well sucker-rod pumping unit, i.e. view A in FIG. 1.

FIG. 5 schematically shows cross section B-B of a yoke in FIG. 3.

FIG. 6 schematically shows cross section C-C of the yoke in FIG. 3.

FIG. 7 schematically shows the drive for the deep-well sucker-rod pumping unit in stowed configuration, i.e. view D (rotated) in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A drive for a deep-well sucker-rod pumping unit comprises a Samson post 1, a walking beam 2, sucker-rods 3, an electric motor 4 coupled to a central gearbox 5 through a belt gear 6. An output shaft 7 of the central gearbox 5 engages pinions 8 of differentials 9 generating reciprocating motions at a different speed of opposite strokes. Output shafts 10 of the differentials 9, which are present on either side of the central gearbox 5, have cranks 11 installed thereon. The cranks 11 are coupled to pitman arms 12 that are coupled to an equalizer 13. Housing parts 14 fixedly attached to crownwheels 15 have cranks 16 installed thereon. The cranks 16 are coupled to pitman arms 17 coupled to the equalizer 13 by means of yokes 18.

The drive for the deep-well sucker-rod pumping unit operates as follows.

The electric motor 4 rotates, through the belt gear 6 and the output shaft 7 of the central gearbox 5, the differentials 9 that generate the reciprocating motions of the walking beam 2 at a different speed of opposite strokes via the cranks 11, 16 and the pitman arms 12, 17. A rotation torque transmitted from the crownwheels 15 to the cranks 16 and further to the pitman arms 17 allows significantly increasing the stroke of the pitman arms 17 and, therefore, the rotation angle of the walking beam 2. This allows for an increase in the stroke length of the sucker-rods 3, thereby improving the kinematics and extending the range of use of the drive.

The present drive for the deep-well sucker-rod pumping unit may be fabricated by using standard equipment, familiar materials and familiar techniques. 

What is claimed is:
 1. A drive for a deep-well sucker-rod pumping unit, the drive comprising: an electric motor coupled through a central gearbox to differentials, comprising pinions and wheels, each differential having an output shaft and a housing fixedly coupled to a crownwheel, wherein the drive is characterized in that the housing of each differential, which is fixedly coupled to the crownwheel, is coupled through a crank to a pitman arm.
 2. The drive for the deep-well sucker-rod pumping unit according to claim 1, wherein the pitman arms coupled to the cranks fixedly coupled to the crownwheels are coupled through yokes to an equalizer on a walking beam.
 3. The drive for the deep-well sucker-rod pumping unit according to claim 1, wherein the pinions of the differentials engage the output shaft of the central gearbox. 